The country of origin of textured silicon wafers

N355523 November 20, 2025 OT:RR:NC:N2:209 CATEGORY: Origin Simeon Yerokun Crowell & Moring LLP 1001 Pennsylvania Ave NW Washington, DC 20004 RE: The country of origin of textured silicon wafers Dear Mr. Yerokun: In your letter dated October 30, 2025, you requested a country of origin ruling on textured silicon wafers on behalf of Canadian Solar International Limited. The items concerned are referred to as textured silicon wafers that will be used in the manufacture of solar cells. Silicon ingots from China or various other countries of origin (Egypt, France, Germany, India, Indonesia, Laos, Malaysia, Nigeria, Norway, Romania, Spain, Turkey, the UAE, Vietnam, Taiwan, Thailand, and the USA), with a chemical composition of 99.99% silicon (Si) are sent to Thailand, where they are manufactured into textured silicon wafers through the process outlined below. The textured silicon wafers are then shipped to the United States to be processed into solar cells. The processing that takes place in Thailand incudes the following: The Wire Saw Cutting Process: The wafer cutting process begins when an ingot of silicon is cut into rectangular bricks. The bricks are then glued and mounted onto a holder and placed into a wire saw. The bricks are then cut into individual wafers. The wire spacing and the wire diameter determine the wafer thickness, typically 150 micrometers. The Gettering Process: The gettering process removes metallic impurities and is an integral part of the wafer fabrication process. It is composed of two major parts, including a wet chemical process to remove saw damage and a high temperature gettering process to reduce metallic impurities. The wafers are bulk-doped with phosphorus (~0.01–0.1 ppm) for a negative-type conductivity attribute. As a result of the Thailand manufacturing process, the phosphorus doping profile measured by ECV (electrochemical capacitance-voltage) contains a high surface doping concentration of 1E19 cm-3, which is four orders of magnitude compared with the base phosphorus doping (1~4E15 cm-3). Phosphorus (the negative dopant) is added during both ingot growth and phosphorous gettering diffusion (Thailand), while Boron (the positive dopant), will be imparted later in the nanocrystalline silicon layer in the Unites States, during solar cell manufacturing, to form the P/N junction. The Texturing Process: Texturing the surface of wafers is essential in the production of high-efficiency silicon. Texturing uses chemicals to create pyramids on the wafer's surface, lowering reflectivity and increasing the amount of light that can be trapped. The Oxidization Process: Thermal oxidation of silicon wafers is a process in which a layer of silicon dioxide is formed on the surface of a silicon wafer under high temperatures. The Oxidization Removal Process & Polishing: The rear side of the silicon wafer is polished to enhance internal light reflection, which can largely enhance the light conversion efficiency. One side of the oxide layers is removed by HF solution while the other side is left to act as a protection layer in the polishing step. The Inspection and Packaging Process: The inspection process ensures that silicon wafers are free of defects, including cracks, edge chips, and breakage. The inspection also ensures that the silicon wafers meet the total thickness variation (TTV) and resistivity requirement and are clean before packaging. A complete in-depth explanation of the manufacturing process has been submitted. When determining the country of origin, the substantial transformation analysis is applicable. See, e.g., Headquarters Ruling Letter (“HQ”) H301619, dated November 6, 2018. The test for determining whether a substantial transformation will occur is whether an article emerges from a process with a new name, character, or use different from that possessed by the article prior to processing. See Texas Instruments Inc. v. United States, 681 F.2d 778 (C.C.P.A. 1982). This determination is based on the totality of the evidence. See National Hand Tool Corp. v. United States, 16 C.I.T. 308 (1992), aff’d, 989 F.2d 1201 (Fed. Cir. 1993). Based upon the facts presented, it is the opinion of this office that the textured silicon wafers have undergone a substantial transformation as a result of the manufacturing steps taken in Thailand. The silicon ingots from China (or various other countries) and the other manufacturing materials undergo a substantial and complex manufacturing process within Thailand. Each of the manufacturing steps undertaken in Thailand is vital to transforming the silicon ingot into a wafer that can be specifically used in the manufacture of solar cells (i.e. texturing to allow the capture of additional sunlight, the phosphorous gettering diffusion process which imparts a negative conductivity attribute to the wafer, the thermal oxidation process that adds a layer of silicon dioxide, etc.). The manufacturing process that takes place in Thailand results in a negativity doped, textured silicon wafer which would be considered an article with a new name, character, and use. As such, the country of origin of the textured silicon wafers will be Thailand. The holding set forth above applies only to the specific factual situation and merchandise description as identified in the ruling request. This position is clearly set forth in Title 19, Code of Federal Regulations (CFR), Section 177.9(b)(1). This section states that a ruling letter is issued on the assumption that all of the information furnished in the ruling letter, whether directly, by reference, or by implication, is accurate and complete in every material respect. In the event that the facts are modified in any way, or if the goods do not conform to these facts at time of importation, you should bring this to the attention of U.S. Customs and Border Protection (CBP) and submit a request for a new ruling in accordance with 19 CFR 177.2. Additionally, we note that the material facts described in the foregoing ruling may be subject to periodic verification by CBP. This ruling is being issued under the provisions of Part 177 of the Customs and Border Protection Regulations (19 C.F.R. 177). A copy of the ruling or the control number indicated above should be provided with the entry documents filed at the time this merchandise is imported. If you have any questions regarding the ruling, please contact National Import Specialist Steven Pollichino at steven.pollichino@cbp.dhs.gov. Sincerely, (for) Deborah Marinucci Designated Official Performing the Duties of the Division Director National Commodity Specialist Division